This application relates to digital audio signal processing.
A musical piece can represent an arrangement of different events or notes that generates different beats, pitches, rhythms, timbre, texture, etc. as perceived by the listener. Each note in a musical piece can be described using an audio signal waveform in the temporal domain having an onset, attack, transient and decay. The energy-time waveform of a note includes a transition from low energy to high energy and then back down to low energy. The time point at which the waveform begins the transition from low energy to high energy is called the onset. The attack of the waveform represents the rise time or the time interval during which the waveform transitions from low energy (e.g., the baseline) to high energy (e.g., the peak). The transient of the waveform represents the time period during which the energy quickly rises and then quickly falls just before the slow decay at the end of the waveform.
Detection of musical events in an audio signal can be useful in various applications such as content delivery, digital signal processing (e.g., compression), data storage, etc. To accurately and automatically detect musical events in an audio signal, various factors, such as the presence of noise and reverb, may be considered. Also, detecting a note from a particular instrument in a multi-track recording of multiple instruments can be a complicated and difficult process.